Process of treating phosphate rock



- m fia Aug. 9. 1921.

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A 41 .638.611 UNITED STATES PATEN-TTOFFICE.

01? I408 ANGETJES, OALII'ORN-IA ASSI NOR TO STO OK- nonoaas SYNDICATE,or os ANGEIVIES, OALH'OBNIA, A conronarrou'or curroams.

My invention relates to a process of treating phosphate rock in order toliberate the hosphoric acid and make the same ava' able in the 'form ofammonium phos- 5 phates. r

- It isan object of this invention to provide a simple, process oftreating phosphate rock with am.-

monium sulphate in a closed retort-to form Jo -ammonium phosphates.

' My invention consists 1n the steps of the "When a pressure of aboutten pounds 1s I used,.the process is ninety per cent (90%) processhereinafterdescribed and claimed.

Finely ground phosphate rock Ga (P0,) 2 is mixed with ammonium sulphateand ll! placed in a closed retort and heated. When mately 300 C.

not exceed 300 The ammonium sulphate reacts on the -p a closed retort toa temperature not to ex The? various combinations and reactions thetemperature reaches about 100 C. the

normal ammonium sulphate is decomposed into acid ammonium sulphate andammonia. The-heating is continued up to approxi- The decomposition" ornormal ammonium sulphate into ammonia and acidammonium sulphate is notcomplete until about 300 C. has been reached. Care should be taken thatthe temperature does C. or else an acid phosphate merely will beproduced. Ammonia it's'elf,-it is well known, dissociates into nitrogenand hydrogen. at a temperature slightly below 500 C.

phosphate rock apparently as follows:

a( O4)2-7'i N 4 4-= 85 l A thetemperature is. increased to above I ofphosphoricacid "and ammonia are uncertain an .complicated, but the'finalproduct .in the retort :is a mixture of ammoniummono 'meta phosphatewhich predominates. with other phosphates such as ammonium hos hate-(NH,) 1 0, with calcium l 'pyrop osp 'ate'Ca' P O, andcalciumsulphate'.

V Apparently the .normal di and mono am -momum phosphates are formed inthe be ginning at certain temperatures and as the temperatures are;elevated the phosphates just mentioned are, probably changed as theammonium radicle is liberated or are com- 0 binedin}. other highercombinations.-

eflicient and economicalfive per cent-(75%) efficient.

I comprising heatin Application filed inns 2a, 1925. Serial 1%. 39,044.

The final product depends more 'or less upon the temperatures at whichthe mixture is held. Care should be taken, as above stated, to keep thetemperature below the decomposition point of ammonia. .Any excessammonia liberated "may be conducted from the retort and recovered by anysuit: able means." 1

The reaction in the'retort appears to be facilitated by pressure, whichmay be regu lated by a valve in the ammonia outletpipe.

eflicient. Without pressure, about seventy- The mixture in the retortconsisting oi ammonium phosphates and calcium sulphate may be. used-as afertilizer, or if de 7 sired, the ammonium phosphate may be separatedfrom ',the. mixture by filtration and crystallization or any othersuitable or preferred method.

.. Various-changes maybe made -in the I steps of the recess by thoseskilled in the art without epartindg from the spirit. ofiny invention,as claime I 'Iclaim:

'1. A process of treating phosphate rock comprismg heating a mixture ofgroundhosphate rock and, ammonium sulphate inaclosed retortto atemperature not-to ex-v rocess of treatingphosphate roclz' ceed 300 C.to produce ammonium phos- .phates,'calc1u1 n sulphates and ammonia.

' 3;A process of treating-phosphate rockcomprismgheating a mixture ofound phosphate rock and ammonium s'ulp ate in a closed retort'underpressure to a temperaturp 'not'to excess 300 C. to; produce ammo'xgiimphosphates and calcium sulphate.

ag closed retort to a temperature not .to exceed 300 C. 'to produceammonium mono" Inaimtimony whereof If have signed my 5 nameto thisspecification." M

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